Prostaglandin analogues for the treatment of glaucoma and ocular hypertension: a systematic review of economic evidence

Systematic methodological review of health state values in glaucoma cost-utility analyses

IMPORTANCE

Describing the characteristics and sources of health state utility values and reporting practice in the literature of cost-utility analyses facilitates an understanding of the level of the transparency, validity, and generalizability of cost-utility analyses. Improving the quality of reporting will support investigators in describing the incremental value of emerging glaucoma interventions.

OBJECTIVE

To describe the state of practice among published glaucoma cost-utility analysis studies, focusing on valuation of health and the quality of reporting.

EVIDENCE REVIEW

We searched several databases including Medline, CINHAL, Embase, Web of Science, Scopus, Biosis previews, the Health Economic Evaluations Database, and the NHS Economic Evaluation Database (NHS EED). We included full-text, English, published cost-utility analyses of glaucoma interventions with quality-adjusted life years (QALYs) as the primary outcome measure to calculate incremental cost-utility ratios. Excluded studies were non-English language, reviews, editorials, protocols, or other types of economic studies (cost-benefit, cost-minimization, cost-effectiveness). Study characteristics, operational definitions of glaucoma health states and health state utilities were extracted. The original source of the health utility was reviewed to determine the scale of measurement and the source of preference weighting. Items from the Systematic Review of Utilities for Cost-Effectiveness (SpRUCE checklist) were used to assess the reporting and quality of health utilities in glaucoma CUA.

FINDINGS

43 CUAs were included, with 11 unique sources of health utilities. A wide range of health utilities for the same Hodapp-Parrish-Anderson glaucoma health states were reported; ocular hypertension (0.84-0.95), mild (0.68-0.94), moderate (0.57-0.92), advanced (0.58-0.88), severe/blind (0.46-0.76), and bilateral blindness (0.26-0.5). Most studies reported the basis for using health utilities (34, 79%) and any assumptions or adjustments applied to the health utilities (22, 51%). Few studies reported a framework for assessing the relevance of health utilities to a decision context (8, 19%). Even fewer (3, 7%) applied a systematic search strategy to identify health utilities and used a structured assessment of quality for inclusion. Overall, reporting has not improved over time.

CONCLUSIONS AND RELEVANCE

This review describes that few CUAs describe important rationale for using health state utility values. Including additional details on the search, appraisal, selection, and inclusion process of health utility values improves transparency, generalizability and supports the assessment of the validity of study conclusions. Future investigations should aim to use health utilities on the same scale of measurement across health states and consider the source and relevance to the decision context/purpose of conducting that cost-utility study.

An analysis of the effectiveness outcomes of economic studies evaluating ophthalmic drugs: a systematic review

PURPOSE

To characterize the effectiveness measures of cost-effectiveness studies (CES) of ophthalmic drugs.

METHODS

A systematic review was conducted in PubMed/Embase until October 2019. Cost-effectiveness studies (CES) evaluating ophthalmic drugs were included. Sources of effectiveness measures were extracted. Data on study design and study outcomes were extracted from sources of effectiveness measures. The adequacy of the sample size of the clinical studies used as sources of effectiveness measures was assessed. If CES have retrieved effectiveness data from multiple sources, the appropriateness of the method to combine the results was analysed.

RESULTS

Forty-five CES were included. Thirty-one (68.9%) retrieved their effectiveness measures from experimental studies, five (11.1%) from observational studies and nine (20%) from other type of data sources. Eight (17.8%) CES used data from a primary outcome of a study as an effectiveness measure, eight (17.8%) used data from secondary outcomes, seven (15.6%) used data from the both primary and secondary outcomes and for 22 (48.9%) it was not possible to identify the outcomes used. From the 23 (51.1%) CES based on a single clinical study, three (6.7%) included data from clinical studies which had an adequate sample size to detect significant differences in the clinical outcomes used as effectiveness measures. From the 17 (37.8%) CES based on multiple clinical studies, only one (2.2%) used and/or reported an adequate method of quantitative synthesis (meta-analysis).

CONCLUSION

A considerable number of CES in ophthalmology were not based on clinical studies with adequate sample sizes and report results from effectiveness measures not assessed as primary outcomes.

Long-term medical management of primary open-angle glaucoma and ocular hypertension in the UK: optimizing cost-effectiveness and clinic resources by minimizing therapy switches

PURPOSE

The objective was to assess the long-term economic consequences of the medical management of glaucoma in the UK.

METHODS

The economic evaluation was conducted using the results from a 10-year Markov model based around 3 key triggers for a switch in medical therapy for glaucoma, namely: lack of tolerance (using hyperemia as a proxy); intraocular pressure (IOP) not meeting treatment benchmark; and glaucoma progression. Clinical data from a comprehensive systematic literature review and meta-analysis were used. Direct costs associated with glaucoma treatment are considered (at 2008/9 prices) from the perspective of the UK NHS as payer (outpatient/secondary care setting). Using this model, the economic consequences of 3 prostaglandin-based treatment sequences were compared.

RESULTS

Drug acquisition costs account for around 8% to 13% of the total cost of glaucoma and, if ophthalmologist visits are included, amount to approximately £0.80 to £0.90 per day of medical therapy. The total long-term costs of all prostaglandin strategies are similar because of a shift in resources: increased drug costs are offset by fewer clinic visits to instigate treatment switches, and by avoiding surgery or costs associated with managing low vision. Under the latanoprost-based strategy, patients would have longer intervals between the need to switch therapies, which is largely due to a reduction in hyperemia, seen as a proxy for tolerance. This leads to a delay in glaucoma progression of 12 to 13 months. For every 1000 clinic appointments, 719 patients can be managed for 1 year with a latanoprost-based strategy compared with 586 or 568 with a bimatoprost or travoprost-based strategy.

CONCLUSIONS

Drug acquisition costs are not a key driver of the total cost of glaucoma management and the cost of medical therapy is offset by avoiding the cost of managing low vision. Economic models of glaucoma should include the long-term consequences of treatment as these will affect cost-effectiveness. This analysis supports the hypothesis that the economic and clinical benefits can be optimized by minimizing therapy switches.

Epidemiology of major eye diseases leading to blindness in Europe: a literature review

The objective of this work was to study the epidemiology of major eye diseases leading to blindness in Europe through a systematic literature review. The literature search was performed using the Medline database (PubMed), with MeSH and free text search terms. Inclusion criteria for the studies were: (a) performed on a healthy population of Caucasian origin aged between 50 and 75 years; (b) diagnosed by ophthalmological examination in accordance with the International Classification of Diseases 10; (c) contained a detailed description of the sampling and diagnostic procedures and data resources; (d) sample size>500, and (e) published between 1990 and 2008. The results of 57 studies on the prevalence and incidence of age-related macular degeneration, diabetic retinopathy and glaucoma are reported, providing an up-to-date and comprehensive overview of these diseases in Europe from an epidemiological perspective.

Cost-effectiveness of screening for open angle glaucoma in developed countries

As all developed countries are struggling with health care costs growing too large and too fast, the current performance and overburden of glaucoma services demand a reappraisal of current management strategies. The performance of the glaucoma care in western countries offers several opportunities to improve the simultaneous under- and over-diagnosis and treatment. Since available resources are finite, they should be targeted to produce the best eye health. There is an obvious need for prioritization of all interventions, including improving case finding. The limited evidence to date indicates that we do not have enough evidence to decide whether systematic population screening could be cost-effective in the developed world. This article gives an overview of the methods of economic evaluation and the evidence on cost-effectiveness of systematic screening for glaucoma in the developed world, need for future research and challenges related to evaluation of increasing economic literature as well as need to change behaviors on the basis of evidence.

Intraocular pressure response to medication in a clinical setting: the Marshfield Clinic Personalized Medicine Research Project

PURPOSE

To estimate glaucoma and ocular hypertension prevalence and to describe temporal trends in prescribing patterns and intraocular pressure (IOP) response to topical medications used in glaucoma and ocular hypertension.

MATERIALS AND METHODS

The medical records of adult subjects enrolled in the population-based Marshfield Clinic Personalized Medicine Research Project were searched to identify participants who had been diagnosed with ocular hypertension or glaucoma and prescribed agent(s) to lower IOP. All IOPs before and after prescription of the IOP agents were recorded.

RESULTS

As of December 31, 2005, 18,773 adults were enrolled in the Personalized Medicine Research Project, 57.1% were female, and their mean age was 50.3 years (range, 18 to 101 y). The overall rate of definite glaucoma in subjects aged 50 years and above was 2.1% (95% confidence interval=1.2, 2.4) and the rate of treated ocular hypertension was 1.4% (95% confidence interval=1.2, 1.7). Topical beta-blockers were the agents prescribed for the majority of subjects until the year 2000, when prostaglandins, first used in 1995, became the primary agent prescribed. In 2005, 75% of subjects used prostaglandin analogs and 46% used topical beta-blockers. The largest relative reduction in IOP in the first 3 months after prescription was observed for prostaglandin analogs (21.4% mean relative reduction), followed by beta-blockers (20.9% mean relative reduction). There has been a significant decrease over time in mean IOP before initiating medical therapy (linear regression beta coefficient=-0.30, P<0.0001, r=0.09).

CONCLUSIONS

In this clinic-based setting, we found that treatment of glaucoma has changed over the past 20 years, with ophthalmologists more likely to begin treatment at lower baseline levels of IOP, and prostaglandin analogs the most commonly prescribed and agent to lower IOP.

A critical review of the full economic evaluations of pharmacological treatments for glaucoma

OBJECTIVE

This literature review aimed to critically assess the 'state of the art' of the full economic evaluations (FEEs) on glaucoma pharmacological treatments. This is the first review that tries to thoroughly assess both costs and consequences of pharmacoeconomic evaluations on glaucoma.

METHODS

A literature search was done on the international databases PubMed and EMBASE, to find all the studies published in English on pharmacological treatments for glaucoma in the period 1997-2006. An economic and a clinical checklist were adopted to analyse FEEs and their clinical sources (CS). Finally, the reliability of the 33 FEEs included in the 15 articles selected was assessed from the health authorities' perspective by applying a critical appraisal checklist of 16 items derived from the economic and clinical variables previously analysed.

RESULTS

The major weakness of the articles reviewed seemed to be the extensive recourse to expert panel opinions and assumptions at each phase of the economic analysis. About one-third of the FEEs even based their clinical efficacy on non-evidence-based sources. The critical appraisal of the CS methodological characteristics showed that their quality was not high either.

CONCLUSION

This review showed that most FEEs on glaucoma suffer substantial methodological limits, mainly due to the scarce quality of available CSs, so public authorities should consider their results very cautiously for healthcare decision making.

A critical review of the full economic evaluations of pharmacological treatments for colorectal cancer

OBJECTIVE

This literature review makes a critical assessment of the methodology of the full economic evaluations (FEEs) conducted on colorectal cancer (CRC) pharmacological treatments.

METHOD

A literature search of the international databases PubMed and EMBASE was carried out to find all the studies published in the English language on pharmacological treatments for CRC in the period 2001-2005. A checklist was adopted to analyse the 13 FEEs selected. Fourteen clinical trials were extracted from the references as sources of efficacy data and were reviewed separately according to a clinical checklist. Finally, the reliability of the 13 FEEs was assessed from the health authorities' perspective by applying a critical appraisal checklist of 16 items derived from the economic and clinical variables previously analysed.

RESULTS

This review found that pharmacoeconomic studies on CRC showed important methodological weaknesses mainly regarding economic evaluation, whilst the sources of clinical evidence were of higher technical quality, although the clinical effectiveness of therapies was not fully sustained by their results.